Rainbow plants
| Rainbow plants | ||||||||||||
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| Systematics | ||||||||||||
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| Byblidaceae | ||||||||||||
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| Byblis | ||||||||||||
| Salisb. |
The rainbow plants ( Byblis ) are the only genus in the family of byblis plants (Byblidaceae) and the order of plants lamiales counted (Lamiales). The eight or so species are all found in Australia and one species is found in New Guinea .
Description and ecology
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Appearance
All Byblis species are upright, weakly woody and not or only weakly branched. The root system is delicate and hair-like. Of the currently eight recognized species, six live as summer annuals and two as perennial plants .
leaves
The leaves of all types are stalk-like and covered all around with fine glandular hairs that secrete a sticky secretion. Interestingly, the tentacles on the leaf surface are all significantly shorter than those on the underside of the leaf, which is partly due to the fact that the leaves are directed extremely upwards, so that the underside of the leaf faces the sun more than the upper side. Small insects are attracted by the sparkling drops of secretion; if they touch it, they die in it, as the sticky slime prevents them from moving. They either die from exhaustion or choke on the thick secretion that seeps into their trachea and clogs them. Unlike the sundew species, however, rainbow plants cannot move their leaves or glandular hairs, which is why they are referred to as “passive sticky traps”.
In addition to the glandular hairs, there is a second type of gland embedded in the leaf surface that is responsible for the actual secretion of the digestive enzymes; these sessile glands are five to ten times more common than the glandular hairs. Byblis is also the only carnivorous plant whose digestive glands are located on both the trunk and the catch leaves.
blossoms
The flowers stand individually at the end of long inflorescence shafts, which are similar to the leaves and are also dark.
The hermaphroditic flowers are radial symmetry and five-fold with a double flower envelope . The five durable sepals are only fused at their base and they overlap like roof tiles. The five petals are only fused at their base, but appear free, and they overlap like roof tiles. The colors of the petals are purple to pale violet, rarely white in Byblis gigantea and Byblis filifolia .
Byblis gigantea and Byblis lamellata only release their pollen through the sound frequency of an approaching pollinator ( vibration pollination ); in the wild these are mostly bees and hover flies . The shape, color and size of the flowers is thought to be an imitation of the flowers of certain fringed lilies ( Thysanotus ). The genus Thysanotus is also native to Australia and many species thrive in the same natural habitats as the rainbow plants. And the flowers of fringed lilies are also fertilized by vibration pollination. With the exception of the self-fertile Byblis liniflora , all species are dependent on cross-pollination for seed formation.
Fruit and seeds
The egg-shaped and bilobed capsule fruits gradually tear open as they dry out, so that the seeds they contain fall to the ground ( barochory ). The black seeds are rounded in shape and have a honeycomb-like relief, whereas Byblis lamellata has lamellas. The germination of many species is set in motion by bush fires after the dry season, with components in the smoke playing the triggering role ( pyrophilia ).
Carnivorous or precarnivorous
The status of the genus Byblis as carnivorous had been repeatedly questioned in the past. At the natural sites, living bugs of the genus Setocoris have been observed in almost all species , feeding on the catches of the plant. It was therefore assumed that, similar to the bug plants , the nutrients in their excrement are absorbed by the plants either through the foliage or the soil. An "indirect" digestion using chitinase-producing mushrooms was also discussed. It was not until 2005 that tests on Byblis filifolia demonstrated that the prey was digested by enzymes excreted from the plant's sessile glands, and shortly afterwards there was also evidence of Byblis liniflora .
Occurrence
All Byblis species are native to Australia . Byblis gigantea and Byblis lamellata occur only in south-western Australia in the greater Perth area, the species of the Byblis liniflora complex only in northern Australia, with Byblis liniflora radiating as far as southeastern Indonesia and southern Papua New Guinea . They grow in peat bogs and marshes and thrive best on sandy soils in heavily sunny or slightly shaded, seasonally wet locations with temperatures between around 5 and 40 ° C.
Status / threat
All Byblis species are native plants in Australia under general protection. Until 2000 they were in Appendix II of the Washington Convention on Endangered Species ; at the request of Australia the protection was revoked. Although the trade is not currently regulated, it is limited to enthusiasts due to the sensitivity of the plants. Most of the plants traded today come from offspring, but mostly only the annual Byblis filifolia and Byblis liniflora are offered, and occasionally Byblis lamellata , other species have to be grown from seeds that are often taken from nature. The Western Australian species Byblis gigantea and Byblis lamellata are endangered by the settlement pressure in the greater Perth area , in particular the drainage of wetlands to gain agricultural land. Byblis gigantea is on the Red List of the International Union for Conservation of Nature and Natural Resources and is considered critically endangered.
Systematics
Taxonomy
The genus Byblis was established in 1808 by Richard Anthony Salisbury . Synonyms for Byblis Salisb. are: Drosanthus R.Br. ex planch. and Drosophorus R.Br. ex planch. Type species is Byblis liniflora Salisb.
External system
Molecular genetic studies have confirmed the genus Byblis , or the family Byblidaceae, as part of the order Mint family (Lamiales); their sister group within the order is uncertain, the families Martyniaceae , Lentibulariaceae and Gesneriaceae come into consideration . At times the Byblidaceae were also assigned the bug plants ( Roridula ), but the latter have now been placed in a separate family, the bug plants ( Roridulaceae ). Another important distinguishing feature between Byblis and Roridula is the biochemical structure of the glandular secretion: that of Byblis is based on cell fluid, that of Roridula is a special resin .
Internal system
Traditionally, only the two species Byblis gigantea and Byblis liniflora were included in the genus Byblis . Mainly through the work of the Australian botanists Allen Lowrie and John Godfrey Conran , further species were first described since the 1980s . About eight species have been known since 2013; they can be divided into two complexes, the Byblis liniflora complex and the Byblis gigantea complex.
Byblis liniflora complex
The six species of this complex, Byblis liniflora , Byblis rorida , Byblis filifolia , Byblis aquatica , Byblis guehoi and Byblis pilbarana are annual herbaceous plants that reach a stature height of 15 to 60 (100) centimeters and a maximum leaf length of 4 to 15 centimeters. The species go from seedling to seed maturity within just a few months and survive the dry season as seeds. The original haploid chromosome number of the Byblis liniflora complex is x = 8, so the diploid number is 2n = 16; for the tetraploid species Byblis liniflora and Byblis guehoi it is correspondingly 2n = 32.
Byblis gigantea complex
The Byblis gigantea complex contains two species: Byblis lamellata and Byblis gigantea . They are perennial subshrubs that reach heights of up to 45 or 70 centimeters. These plants survive dry periods through an underground rhizome from which they then sprout again. Their leaves are up to 20 centimeters long. The basic chromosome number of the Byblis gigantea complex is x = 9, the diploid chromosome number of both species is correspondingly 2n = 18.
Species and their distribution
- Byblis aquatica Lowrie & Conran : It occurs only in the northern Northern Territory .
- Byblis filifolia Planch. : It occurs in north-western and central-northern Australia in Northern Territory and Western Australia. The number of chromosomes is 2n = 16.
- Byblis gigantea Lindl. (Syn .: Byblis lindleyana Planch. ): They in southwest Australia in Western Australia.
- Byblis guehoi Lowrie & Conran : It wasfirst describedin 2008 from northern Western Australia .
- Byblis lamellata Conran & Lowrie : It was first described in 2002 from west-southwestern Western Australia.
- Byblis liniflora Salisb. (Syn .: Byblis caerulea R.Br. ex Planch. ): It occurs from New Guinea to northern Australia.
- Byblis pilbarana Conran & Lowrie It was first described in 2013 from Western Australia.
- Byblis rorida Lowrie & Conran : It occurs only in northern Western Australia.
Paleobotany
In 2004, a single mid- Eocene fossil seed was found in South Australia ; a comparison with today's Byblis species demonstrated the close relationship of the plant to the Byblis liniflora complex. The "plant", as it is only known as a seed, was classified as a Parataxon , ie as a provisional species, in the rainbow plant family.
etymology
The scientific generic name refers to the Greek source nymph Byblis . According to Greek mythology , she is the daughter of the gods Miletus and Kyaneia . The Roman poet Ovid describes Byblis in his Metamorphoses (IX, v. 454–664) as the granddaughter of Apollo . The forecast for she is unhappy in her twin brother Kaunos love. Rejected by him, it literally melts before his eyes into countless, shimmering tears and finally turns into a spring. According to another version, she searches in vain for her brother in the deepest forests of her country, soon collapses, exhausted and crying, and is transformed into a spring by forest nymphs. The fine droplets secreted by the leaves of the plants are supposed to remind of their tears.
The common German name rainbow plant goes back to the shiny droplets of secretion in which the light is refracted differently depending on the incidence and thus causes the eponymous rainbow effect.
literature
- Wolf-Ekkehard Lönnig: The evolution of carnivorous plants: what selection cannot achieve - the example of Utricularia (water hose); scientific non-fiction book . Monsenstein and Vannerdat, Münster 2012, ISBN 3869914874 .
- Allen Lowrie : Carnivorous Plants of Australia. Volume 3. University of Western Australia Press, Nedlands 1998, ISBN 1-875560-59-9 .
- Allen Lowrie, John G. Conran: A taxonomic revision of the genus Byblis (Byblidaceae) in northern Australia. In: Nuytsia . Volume 12, No. 1, 1998, pp. 59-74 .
- John G. Conran: The embryology and relationships of the Byblidaceae. In: Australian Systematic Botany. Volume 9, No. 2, 1996, ISSN 1030-1887 , pp. 243-254, doi : 10.1071 / SB9960243 .
- John G. Conran, Allen Lowrie, Jessica Moyle-Croft: A revision of Byblis (Byblidaceae) in south-western Australia. In: Nuytsia. Volume 15, No. 1, 2002, pp. 11-19 .
- John G. Conran, Roger Carolin: Byblidaceae. In: Joachim W. Kadereit (Ed.): The Families and Genera of Vascular Plants . Volume 7: Flowering plants, Dicotyledons. Lamiales (except Acanthaceae including Avicenniaceae) . Springer, Berlin / Heidelberg / New York 2004, ISBN 3-540-40593-3 , pp. 45–49 (English, limited preview in Google Book Search).
Individual evidence
- ^ A b c d Aaron Ellison, Lubomír Adamec: Carnivorous Plants: Physiology, Ecology, and Evolution. Oxford University Press, Oxford (UK) 2017, ISBN 0191085391 , pp. 132-134.
- ↑ a b Wolf-Ekkehard Lönnig: The evolution of the carnivorous plants . Pp. 212-214.
- ^ A b John G. Conran, Roger Carolin: Byblidaceae. In: Joachim W. Kadereit (Ed.): The Families and Genera of Vascular Plants . Volume 7: Flowering plants, Dicotyledons. Lamiales (except Acanthaceae including Avicenniaceae) . Springer, Berlin / Heidelberg / New York 2004, ISBN 3-540-40593-3 , pp. 45–49 (English, limited preview in Google Book Search).
- ↑ Irmgard Hartmeyer, Siegfried Hartmeyer: Byblis filifolia rehabilitated as real carnivores. In: The Taublatt. No. 53 = No. 3, 2005, ISSN 0942-959X , pp. 4-5, ( online ).
- ↑ Bartosz J. Płachno, Andrzej Jankun: Phosphatase Activity in Glandular Structures of Carnivorous Plant Traps. In: XVII IBC 2005. = XVII International Botanical Congress. Vienna, Austria, Europe. 100 Years after the II IBC in Vienna 1905. Abstracts. sn, Vienna 2005, p. 510, P1716, ( digital copy (PDF; 7.61 MB) ).
- ↑ a b c d e f g h i Rafaël Govaerts (Ed.): Byblis. In: World Checklist of Selected Plant Families (WCSP) - The Board of Trustees of the Royal Botanic Gardens, Kew . Retrieved December 15, 2018.
- ^ A b c Allen Lowrie, John G. Conran: Byblis guehoi (Byblidaceae), a new species from the Kimberley, Western Australia. In: Telopea. Volume 12, No. 1, 2008, ISSN 0312-9764 , pp. 23-29 .
- ^ A b John G. Conran, Andreas Houben, Allen Lowrie: Chromosome numbers in Byblidaceae. In: Australian Journal of Botany. Volume 50, No. 5, 2002, ISSN 0067-1924 , pp. 583-586, doi : 10.1071 / BT02007 .
- ^ Byblis filifolia at Tropicos.org. In: IPCN Chromosome Reports . Missouri Botanical Garden, St. Louis
- ↑ Byblis pilbarana in the Red List of Endangered Species (classified as “not endangered”) (English); last accessed on July 31, 2018.
- ^ John G. Conran, David C. Christophel: A Fossil Byblidaceae Seed from Eocene South Australia. In: International Journal of Plant Sciences. Volume 165, No. 4, 2004, ISSN 1058-5893 , pp. 691-694, JSTOR 386555 .
- ↑ Umberto Quattrocchi: CRC World Dictionary of Plant Names: Common Names, Scientific Names, Eponyms, Synonyms, and Etymology. CRC Press, Boca Raton (FL) 1999, ISBN 0849326737 , p. 381.
- ↑ Roland Granobs: Studies on the representation of Roman history in Ovid's Metamorphoses (= studies on classical philology , 108th volume). P. Lang, Frankfurt am Main 1997, ISBN 3631319533 , p. 74.
